ML20084K313
| ML20084K313 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 07/18/1974 |
| From: | COMMONWEALTH EDISON CO. |
| To: | US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20084K292 | List: |
| References | |
| AO-50-254-74-8H, NUDOCS 8305190272 | |
| Download: ML20084K313 (2) | |
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REPORT NUM8ER: A0 25.4/74-8h j
REPORT DATE: July 18, 1974 OCCURRENCE DATE: July 5,1974 FACILITY: quad-Cities Nuclear Power Station Cordova, Illinois 61242 IDENTIFICATION OF OCCURRENCE:
Excessive leakage from the volume enclosed by reactor water cleanup system iso-lation valves 1-1201-82 and MD-1-1201-80.
l CON 0lTIONS PRIOR TO OCCURRENCE:
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Reactor in cold shutdown condition for refueling outage, reactor water cleanup system out of service and piping drained.
DESCRIPTION OF OCCURRENCE:
Local leak rate test!ng of the Unit One primary containment Clean-Up System valves was in progress on July 5,1974 Manual valve 1-1201-82 was placed in the closed position by normal means. M0 1201 -80 was placed in the close position after the volume between the 1201-80 and 1201-82 valves was drained by actuating the control room switch.
i The leak test was performed by pressurizing the volume between the valves through i
the pressure test valves 1-1201-126 and 1-1201-127 to a test pressure of 48 psig.
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The leak rate was in excess of the limit of 18.36 SCFH (5% Lto) for any primary 1
containment isolation valve per Technical Specification 4.7.A.2.i.(2)(b).
The 1-1201-80 was taken out of service and repairs were performed. The valve seat was found to be in good shape. The valve globe was found to be wire drawn where it meets the seating surface. The globe was relapped.
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A subsequent leak test after repairs showed the valve to have no leakage.
DESIGNATION OF APPARENT CAUSE OF OCCURRENCE.
The apparent cause of the leakage was the condition of the valve globe.
It showed signs of being wire drawn by the hot water passing through the valve body.
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i ANALYS1S OF OCCURRENCE:
The leakage of the M0-1-1201-80 valve was in excess of Technical Specification limitations.
If an accident had occurred, some leakage would have occurred. Since the manual valve 1-1201-82 could have been closed readily in the MSIV room the amount of water lost from the reactor would have been small. Any water that was i
lost could have been easily made up to maintain reactor water level.
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A0 254/74-8h July 18, 1974 Water that would have leaked would have been contained in the cleanup heat ex-changer room. The consequences from the standpoint of public health and safety or personnel exposure would have therefore been minimal.
CORRECTIVE ACTION:
Normal maintenance procedures for relapping a valve globe corrected the problem.
The Unit Two 1201-80 valve will be leak tested during its first refueling outage.
FAILURE DATA:
No previous failures have occurred at Quad-Cities Station.
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